The integrated circuit technology has shrunken electronic circuits to the micron and submicron level. Surface mount technologies improved the printed circuit board density. The application specific integrated circuit (ASIC) put electronic circuits that occupied a printed circuit board into a single chip. Through these advances, the miniature size of the integrated circuit greatly enhanced its versatility and enabled its application to usage previously believed to be impossible.
The International Standards Organization (ISO) has established the standards of the credit card or personal identification card. These cards are equipped with a readable magnetic strip to provide storage and retrieval of information. Usage of these cards has expanded to debit cards, telephone calling cards, company personal identification badges, automated teller machine banking cards, vending cards, etc. However, these cards are not without disadvantages. These cards can only be read with a magnetic strip reader by passing the magnetic strip through it. Often a card must be inserted and passed through the reader repeatedly due to improper positioning or operation. Because the magnetic strip medium resides on the surface of the card, it is easily damaged due to improper handling and storage of the card. It is therefore desirable to provide a card that may be read with speed and in a contactless manner. Moreover, it is desirable to provide "smart" cards with added capabilities other than the basic storage and retrieval of data.
The ISO sets the standard dimensions for the credit card, which are 86.times.54.times.0.76 mm. For embedding integrated circuits therein, the critical dimension is the thickness of the card, which is 0.76 millimeters (mm) or 760 microns (.mu.m). With capacitor thickness of approximately 500 .mu.m, integrated circuit die of approximately 300 .mu.m, and the required card packaging material of approximately 250 .mu.m, typical integrated circuit assembly methods and techniques based on surface mount devices mounted on printed circuit boards or substrates are not applicable.
Accordingly, it is desirable to achieve an assembly of integrated circuits that can be accommodated within the standard dimensions of the ISO credit card.